Quick Tip: Why You Have Low ClickThrus on Mobile Device & How to Fix It
On a mobile device, Google ads are less likely to be seen because there's simply less space on-screen for ads to show compared to a desktop.:
If an ad doesn't rank in the top 2 spots, they probably won't be seen at all. If you notice lower Click-thru-rates from mobile devices, you're probably ranking below position 2.
To overcome this, create a separate, mobile-only version of the campaign and choose the following as a bidding strategy: "Target search page location -> Top of the first results page."
This empowers Google to update your keyword bids so you outbid your competition and rank at the top of the page.